The overall objective of this project is to measure dynamic properties of animal cell surfaces in order to characterize structures and mechanisms involved physiological functions such as regulation of growth, interactions among cells, and response to activators such as hormones or growth factors. We have recently measured the lateral mobilities of several different lipid probes and proteins in the plasma membranes of a variety of cell types. During the coming year we will use these methods as well as video microscopic techniques to study several areas. 1) Interactions of enveloped virus with cell surfaces. We will undertake studies of the mechanisms of budding of vesicular stomatitis virus (in collaboration with Dr. John Lennard) and of Sindbis virus (in collaboration with Dr. Milton Schlesinger) and of the effects of Sendai virus on the mobility of the plasma membrane proteins of cells to which it's absorbed. 2) Effects of oncogenic transformation on cell surface mobility. Various cell surface components will be tested on cells undergoing temperature sensitive transformation by mutants of Rous sarcoma virus. 3) Dynamic properties of plasma membranes of macrophage. An attempt will be made to relate observations to functions of the cell.